Supermodel Heidi Klum‘s personal trainer has moved in with her to help get her into shape.

The German supermodel is desperate to shed the weight she gained while pregnant with daughter Lou - her fourth child who was born last month - before a Victoria’s Secret catwalk show next week and has embarked on a grueling diet and exercise regime under the guidance of expert David Kirsch.

A source said, “Heidi’s swapped processed carbs, sugar, dairy and fruit for egg-white omelettes, spinach salads and grilled tuna with quinoa. She’s determined to wow everyone when she walks. She’s pushing herself through gruelling twice-daily workouts.”

Heidi has previously admitted she is struggling to lose her baby weight and finds it much tougher than she did after having her other children, Leni, five, Henri, four, and Johan, three: “I wouldn’t say I’m back in shape yet. Everything changes when you get older. It was different when I was 31 with the first one and now being 36 with the fourth one.”

She is now hitting the treadmill and eating sensibly in a bid to get back in shape as she fears she will remain bigger forever if she doesn’t act now: “I think that if you wait too long and it sticks there it stays that way forever. I have to be motivated.”